Financial Guarantee Insurance - Summary of Percentage Ceded to Reinsurers and Reinsurance Recoverable and Rating Levels (Detail)	Dec. 31, 2022
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Percentage of Ceded Reinsurance Recoverable Represented by Top Three	84.20%

Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]

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